Optoelectronic modules, such as optoelectronic transceiver or transponder modules, are increasingly used in electronic and optoelectronic communication. Optoelectronic modules generally include one or more optical subassemblies (OSAs), such as a transmitter optical subassembly (TOSA) and/or a receiver optical subassembly (ROSA). Each OSA of an optoelectronic module is generally positioned proximate an optical port of the optoelectronic module. Each optical port is configured to receive an optical fiber connector, such as an LC or an SC connector, such that the corresponding optical fiber is capable of optically and mechanically interfacing with the OSA.
Optoelectronic modules also generally include one or more printed circuit boards having electronic circuitry. The electronic circuitry of a printed circuit board can create electromagnetic radiation (EMR). When EMR is inadvertently emitted from an optoelectronic module, the EMR can cause electromagnetic interference (EMI) in nearby electronic devices which can degrade the functionality of those electronic devices. Therefore, it is important to control the inadvertent emission of EMR from optoelectronic modules. In addition, as host devices are configured to simultaneously interface with increasing numbers of optoelectronic modules, and as data rates of optoelectronic modules increase, the inadvertent emission of EMR becomes increasingly problematic.
Another related problem is the electromagnetic susceptibility (EMS) of optoelectronic modules. The EMS of an optoelectronic module is the degree to which the optoelectronic module is subject to malfunction or failure under the influence of electromagnetic radiation. Therefore, it is also important to control the inadvertent introduction of EMR into optoelectronic modules.
Controlling the emission/introduction of EMR from/into an optoelectronic module is generally accomplished by surrounding the optoelectronic module, as much as possible, with a housing formed from an electrically conductive material, which limits the emission/introduction of EMR, thus decreasing EMI in nearby electronic devices and in the optoelectronic module. It can be difficult, however, to control the transmission of EMR through required openings in the housing of an optoelectronic module, such as the optical ports that are configured to receive optical fiber connectors.
As mentioned above, each OSA in an optoelectronic module is generally positioned proximate an optical port of the optoelectronic module. Each OSA is generally formed from a non-electrically conductive material, such as plastic, and is therefore not effective at limiting the transmission of EMR. EMR may, therefore, pass through the OSA and exit and/or enter the optoelectronic module through the corresponding optical port.
Attempts have been made to control the amount of EMR that passes through an OSA. One such attempt involved shielding a plastic OSA by coating the OSA with metal. This attempt proved problematic, however, due to the increased effort required to securely adhere metal to the plastic OSA, which resulted in the metal coating flaking off, thus decreasing the effectiveness of the shielding. This attempt also failed to address the large hole in the shielding where the OSA interfaces with an optical fiber.
Another attempt at controlling the amount of EMR that passes through an OSA involved forming the OSA from metal instead of plastic. This attempt also proved problematic because of the increased cost in manufacturing a metal OSA over a plastic OSA. This attempt also failed to address the large hole in the shielding where the OSA interfaces with an optical fiber.
In light of the above discussion, a need currently exists for an OSA that is effective at limiting the transmission of EMR out of and/or into an optoelectronic module into which the OSA is integrated.